I had installed the
recovery-thunderc-v-1.2.0-GNM.img
available here
Custom Recovery Optimus V - Android Forums
When I pissed about the internet not working one day on my rooted stock rom I went to the Settings Menu under privacy and decided to erase all data to get it to stock. Well it didn't like that i had the thunder recovery and kept on boot looping to it.
No matter what Rom I loaded gingerbread, stock or whatever it would just loop to recovery. Well It wasn't the ROM that was the problem it was the recovery.
The recovery must have left some original LG code or area that has a flag that keeps on telling it to reboot to recovery and clear cache but the hacked recovery doesn't turn off that flag (wherever it may be) and it loops.
When you flash a nandroid backup with Thunder recovery it won't flash the recovery. Thankfully Thunder has ADB root setup when you boot to recovery so you just have to flash your stock rom nandroid backup and then flash the STOCK recovery image overwriting the thunder recovery image MANUALLY. This will allow it to reset that nasty LG flag and then it proceeds to boot to your stock image.
Then the boot loops stop. I would get away from stock just in case you should acidentally use the settings privacy menu to wipe your device.
Here is the stock image with some instructions but you can't really use them completely. You will need to adb the STOCK recovery from within your custom bootloader.
How to: Return your Optimus V to Stock(Tested working)
Just wanted to let you guys know what is going on. Don't do anything stupid and really screw up your phone.
You need to save battery life to fix your phone don't waste it, it won't charge without booting. Although you can get an external "Universal Travel Charger" that will charge any kind of phone battery.